Referring to FIGS. 1 and 2, a conventional musical instrument stand has a tripod device 11, a main shaft 12 disposed on the tripod device 11, a brace device 13 disposed on the main shaft 12, and two brackets 113. The tripod device 11 has a main leg 111 and two auxiliary legs 112. Each of the brackets 113 is connected to the corresponding auxiliary let 112. The main shaft 12 has a L shape. The brace device 13 has a U-shaped bracer 131 having two arms 134, an end rod 133 disposed on one of the arms 134, and a locking bar 132. The locking bar 132 has an end groove 136, and an end hole 135 to receive the end rod 133. One end of the U-shaped bracer 131 has the end rod 133 engaging with the end hole 135, and the other end of the U-shaped bracer 131 engages with the end groove 136. The locking bar 132 is rotated along a direction A. Then a guitar 14 is placed on the conventional musical instrument stand. The brackets 113 and the brace device 13 support the guitar 14. Since the U-shaped bracer 131 is made of a plastics material, the end hole 135 of the locking bar 132 will be enlarged after a long period of usage. Therefore, the end rod 135 will be disengaged from the end hole 135 of the locking bar 132 easily.